The argument about monkeys beating investors has nothing to do with investor biases. The point is that professional investors charge fees for their stock picki

The argument about monkeys beating investors has nothing to do with investor biases. The point is that professional investors charge fees for their stock picking strategies and that due to the fees alone, these returns will be smaller than randomly choosing stocks (market weighted) with no fees. The moral of the story is that few people can successfully beat the market, and if they could they wouldn't be letting you in on their strategy for a reasonable fee.